Photographic silver-halide emulsions sensitized with azamerocyanine dyes



Patented Oct. 30, 1951 UNITED PHOTOGRAPHIC SILVER-HALIDE EMUL- SIONS SENSITIZED WITH AZAMERO- CYANINE DYES Thomas R. Thompson, Bing hamton, N. Y., as-

signor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Original application July 16, 1946, Serial No. 683,975, now Patent No.-2,496,8.99, dated Feb-- ruary 7, 1950. Divided and this application I September 25, 1946, Serial No. 699,354

4 Claims. 1

This invention relates to photographic gelatino-silver-halide emulsions, and more particularly to photographic emulsions sensitized by means of azamerocyanine dyes.

It is known that quaternary salts of heterocyclic nitrogen compounds having various reactive groupings such as amino, imino, acetanilido, and thelike, can be condensed with various substances to give dyes of the cyanine type, that is, dyes in which the two nuclei are joined by a monoor polymethine chain containing one or two nitrogen atoms.

United States Patents 2,080,049-50 describe the preparation of cyadiazine and carbocyazine dyes by condensing a heterocyclic nitrogen base or its quaternary salt having an amino or imino group in the a or y position to the nitrogen atom thereof with ethyl orthoformate or p-dimethylamino-ben'zaldehyde to give, respectively, compounds characterized by the following formulae:

S\ V k Q In United States Patent 2,298,732, Brooker et al.

have described a process for preparing a polymethine base, without the acid elements, from a hemicyanine dye' by means 'of alkali metal hydroxides, and which base is'illu'stratedby'the following formula:

. V 2 I f 1 ylrhodanine); to give a compound represented by the following formula:

I have now found that a primary amino substituent group in the oi-position of a heterocyclic nitrogen quaternary salt is capable of reacting with an acetanilido group of a 5-membered ketomethylene heterocyclic compound to give an analogous series of azamerocyanine dyes having one nitrogen atom in the monomethine chainthereof. Said nitrogen atom is bound to a carbon atom of the methine chain in the form of an azo methine linkage. It is the accepted practice to form compounds containing an azo methine group by -the' reaction of an aldehyde with a primary amine and this is illustrated by the styryl type dyes 'of the patents referred to above. It. was, therefore, surprising to find that compounds containing such group may also be obtained by re. actingan acetanilido-methine group with a primary amino group contrary to the usual practice.

An object of the present invention is to provide photographic silver-halide emulsions sensitized with azamerocyanine dyes.

A further project is .to provide such azamerocyanine dyes which are added to photographic silver halideemulsions or coated thereon as an over-coating, whereby the sensitivity of the photographic emulsion is increased.

Other objects will appear hereinafter.

The azamerocyanine dyes prepared according to. the present invention. are characterized by the following general formula: v

wherein R represents an alkyl or aralkyl group, e. g., ,methyl, ethyl, propyl, butyl, etc benzyl; methyl benzyl, ethyl benzyl, and the like, Y repre-' sents the atoms necessary to complete a 5-membered heterocyclic nucleus e. g., substituted or unsubstituted rhodanine, oxazoledione, thiazblone, pyrazolone, hydantoin (imidazolone); thiohydantoin, and the like, and Z represents the atoms necessary to complete a 5-membeied or '6'- membered heterocyclic nitrogenous nucleus of the type usual in cyanine dyes such as benzox- Mole, enzet iazp e. em nazo nanh h xazole, naphthothiazole, oxazole, oxazoline, pyrie dine, quinoline, selenazole, selenazoline, naphthoselenazole, thiazoline, thiodiazole, and the, like. 7

The process of preparing the above'azamerocyanines comprises heating, under-grefiux conditions, 1 mol of a 2-amino heterocyclic nitrogenous quaternary salt with 1 mol of. a. 5-memb ered heterocyclic intermediate derivediromrhodanine, oxazoledione, thiazolone, pyrazolo'ne, hydantoin, thiohydantoin, and the like, having a reactive acetanilido group linked to a carbon atomf a monomethine chain adjacent to-a'ketogmupof such intermediate in the presence.v of, a basic condensing agent and a tertiary baseas a cata- The 2-amino heterocyclic nitrogenous quaterlll-rfifl a a e r n ese tei e eeneral for,- mula: I r

wherein R and Z have the same values'as above, and X represents an anionic radical, e; g., Cl, Br, I, C104, $040113, SO4C2H5, SO3C6H4CH3, and the like:

v As; examples of suitable l-amino heterocyclic nitrogenous quaternarysalts may belmentioned 2+aminobenzothiazole, Z-aminobenzoxazola, 2- aminobenzoselenazole, 2-aminoselenazole, 2,-ami1 noeselenazoline, 2.-aminooxazo1ine, Z-amino-- phenyloxazole,. 2.-aminoeemethylthiadiazole,. 2-..- amino 5.l-methyloxdiazole; 2 -aminopyridine, 2- aminoquinoline,. Z-amino-a-naphthothiazole,. 2- aminoes-naphthothiazole 2 amino 5' ethoxybenzothiazole, Z-aminothiazole, andathe like, as

the methiodide; ethiodide, propiodide,methyl-pav toluenesulfonate,andthelike. '7 l a, -The 5-membered heterocyclic intermediates :derived from rhodanine,oxazoledione, etc., and .the methods-fon their preparation aredescribed:- in United StatesJ Patent .2;18.6-,608i and represented by the general formula: V 1 i,

wherein, Y has the same value asabove. More particularly, the compounds represented-by. this general formula, areas follows;

1 phenyL- 3 methyl leacetanflidomethylene-F);

li-py-ridyl 3 methyl-4 acetanilidomethy1ene-5 pyrazolone ,7 l

5-acetanilidomethylene-3-pheny1rhodanine 5-acetanilidomethylene-3-ethylrhodanine 5-acetanilidomethylene-3-al1ylrhodanine 5 acetanilidomethylene- 3-ethyl-2-thio-2,4 (8,5)

oxazoledione 5 acetanilidomethylene-Z-diphenylaminoal(5)- thiazclone- 5-acetanilidomethylene-3-ethyl -l-phenyl-2-thio- 'h de 3-ac etan il idomethylene-5-methyl-2-thiophen0ne,.

\ and-the like 7 As-acondensin a ents employed in the preparaw .2 Qfetheiaza m v nm ye Q h zp e ent a enti ll; l leite mayi be emplox d bas c, c

4 binding) agents, such as pyridine, methyl pyridine, dimethyl pyridine, ethyl pyridine, ethylmeihyll x d l ethxl. py id ne uinolin and the lik ,ith basic; catalysts ,,such as tri- 5 ethylamine', tributylamine, sodium or potassium carbonate. In general, the amount of condensing agent may vary within wide limits, e. g., from 1 to ;2 5 m o l s; Concentrations ranging from 1 mol to about molsare preferred, however.

1. mollof 2-aminobenzothiazo1e ethiodide is condensed withl, mol of 5-acetanilidomethy1- enq-bfj-allvl-rhodanine in the presence of a condensing,agent andgcatalyst such as pyridine and triethylamine, a reaction occurs Which may be The following examples describe. in. detail, the methodsfor;accomplishingthe aboveohjects, but iti im e" un er toodthat. then are inserted merely fonthelll rpose-of illustrationlando-arenot tobe co s ruedasl m tatives r Example I sHas 5- 3-ethy1-2-benzothiazolylideneiminoniethylene -3- zhqqamm A mixture of 4.5 grams of 2-aminobenzothiazole ethiodide, 4.8 grams of 5-acetan'ilidomethylene+3=al1y r 9 ae na 5,0 ccvoiup r din and 5 eel-0f. l iethxlamiueyas. heated atr flux ,fortwo: hours The re t p .mi turamw i u dwit three volumes'cof'water, and'a'iter cooling'overnight, the product was filtered and purified by, boiling out With methanol? Further purification was obtained by crystallization" from "a; methanol dioxane mixture. The melting point was 197- 199 0., with a yield of 3.0 grams (83% efcthe theoretical)? A silver chloridelpho tographlc emulsion was sensitized with a maximum at 520 m a r Example II JHA: 1..

3 5- (3 ethyl fi methyl-2-beniothiazolylideneiminomethylene) 7 sauum danme A mixture of 2.5 grains of 2-ami'no-6-methylbenzothiazole ethiodide, 2.5 grams of S-acetanilidomethylene-3-al1ylrhodanine, 25 cc. of pyridine and 3 cc. of triethylamine was heated at reflux for two hours. The product crystallized from the reaction mixture on cooling. After boiling out with methanol, the orange crystals melted at 24'7249 C., and sensitized a silver chloride photographic emulsion with a maximum of sensitivity at 525 m Example III 5- (3-ethyl-6-eth0xy-2-benzothiazolylideneiminomethylene) 3-allylrhodanine A mixture of 5.0 grams of 2-amino-6-ethoxybenzothiazole ethiodide, 5.0 grams of 5-acetanilidomethylene 3 allylrhodanine, .40 cc. of pyridine, and 5 cc. of triethylamine was heated at reflux for two hours. The reaction mixture was diluted with three volumes of water and the precipitated product purified by boiling out with methanol. After crystallization from a methanol-dioxane mixture, the orange crystals melted at 187-188" C. This dye sensitized a photographic silver chloride emulsion with a sensitization maximum at 540 m Example IV lsHi 5- (3-ethy1-6,7-benzo-2-benz0tl1iazolylideneiminomethylene) :45

3-allylrhodanine One gram of 2-amino-a-naphthothiazole ethiodide, 0.95 gram of 5-acetanalidomethylene3- allylrhodanine, 15 cc. of pyridine, and 3 cc. of triethylamine was heated at reflux for two hours.

z photographic emulsion to 565 nm with a maximum at 530 mp. .1

Example VI 5- (l ethyl-2 pyridylideneiminomethylene)-8-allylrhoda1iihe A mixture of 5.4 grams of Z-aminopyridine ethyl p-toluenesulfonate, 5.8 grams of 5-aeetani- 1idomethylene-3-al1ylrh0danine, 20 cc. of pyridine, and 5 cc. of triethylamine was heated at Two volumes of water were added, and after cooling, the dye separated in the form of crystals. Purification was efiected by boiling out with methanol, yield 0.4 gram. This dye extends the sensitivity of a silver chloride emulsionto 570 m with a maximum of 535 mu.

5- (3-ethyl-6-methoxybenz0thiazolylideneiminomethylene) 3-ally1rhodanine A mixture of 0.64 gram of 2-amino-6-methoxybenzothiazole ethiodide, 0.64 grams of 5-acetanilidomethylene-3allylrhodanine, 15 cc. of pyridine, and 3 cc. of triethylamine was heated at reflux for two hours. The dye separated on cooling and was purified by boiling out with methanol. The dye in the form of orange crystals melted at 207-208 C., and sensitized a silver chloride reflux for two hours. The dye was precipitated by the addition of three volumes of water" and purified by boiling out with methanol. Yield 5 grams, melting point 138-140 C. 1

Example VIII I I 0=NoH=o--- s l g p 0=o =s N N aHa 5- (3-ethyl-5-phenyl-2-benzoxazolylideneiminomethylene) 3-allylrhodanine 1 A A mixture of 1.8 grams of 2-amino-5-phenylbenzoxazole ethiodide, 1.6 grams of 5-acetanllidomethylene 3 allylrhodanine, 15 cc. of pyridine, and 3 cc. of triethylamine was heated at reflux for two hours. Two volumes of water were added, and after cooling overnight crystals were obtained which were further purified by boiling out with methanol. The yellow crystals melted at 248-249 C., and sensitized a silver chloride photographic emulsion with a maximum at 490 m Example IX J; O=Al =8 GaHl 5-(1-ethyl-2-quinolinylideneigninomethylene) -3-a1ly1- rhodanlne sthe .sensitizatiQn- T e rztll i ee ll. -,d1;awing V illustrate; the, sensitizing properties of 11 T1118, appli 5ft? 'i 1 .1.: it: -33, 1 Mom, 1 I A mix e of 0.4 gram of ethiodide, 0.4 gram; of flg acetamlidome y allylrhodanine, 10 cc. of pyridine, and '2 cc. of triethylamine was heated at reflu gfor two hours. The product wa purifiediby boiling out with 5 N methanol. It melts it 2'19 220" 0., This dye sensitizes a photographic bromide emulsion with a maximum at .530 m In the preparation of emulsions containing th e a amer q aniee dyes ..ine d emex b ,d solved in methyl onethyl alcohol containin'g from ,i9,5.0, ,m i rem$ he We ad d. a liter of emulsion, While in general practice itf ma not an thos given ewe, eee ra or. em c- LW I u t$h@mq :@n m from 5 to 25 milliams aresufiicient toobtain the maximumfseni ineh ectll weveir ,1 we h ki fifi lf c-i he u n es.,ciu t f ieei i. s. th

'jgnost suitable, amounts willin eachcasebe found its; ew,.c mp ra v ex r men a lil may be added to the emulsion in the form 'ofa solution. Suitable solventsmay be the alcohols,

for instance, methyl 'orethyl alcohol, which.

may be anhydrous or diluted with a small volume of water. In actual practice, the dyes are applied to theemulsion during any stage of its production. However, they arev preferably added to the finished-emulsion beforebeing cast.

The diagrammatic spectrograms constituting the accompanyi drawing illustrate the regions of the ,SP QI' T A to which the azamero cyanine dyes will sensitizea silver chloride emulsion congbe neeessary-t add the dye in -amounts lariger 2. A photographic gela'tino- 'lver malice emuly5 sion containing a dye of the following formula:

5 o=i r-oiei o--jJ E0 =8 H n I I ca Ha p *egenem uve; 2 a

'-.-tia me=. 4; 5.%e veni alide n ithe, extent of s; o f this the 'dyes prepared according to Examples 1, IV,

and'Vi-w;

While there have beenw-pointed out above cer- ;tain preferred embodiments of the invention, the 46 sion containing an azamerocyanine dye,-selected I from the group-of dyes characterized by lowing general formula:

the fol- 55 sion enta'ifiifig rate-of the following'formulai $2115 4. A photographic ;g e1a 1;olsitehanazstlsion containing a'dye of the following formula:

Name B tch 1 2,078,233 Brooker Apr. 27,4937 i 2,080,049 eKendall ,May 11,;1937 2,080,050 Kendall May11,,-197 2,265,908 Kendall Dec. 9, 1941 

1. A PHOTOGRAPHIC GELATINO-SILVER-HALIDE EMULSION CONTAINING AN AZAMEROCYANINE DYE, SELECTED FROM THE GROUP DYES CHARACTERIZED BY THE FOLLOWING GENERAL FORMULA: 